Objective: Circulating tumor cells (CTC) have become an important part of liquid biopsy, which have underwent a process from simple counting to molecular typing and genotyping. To this end, we used Cellcollector to verify the effectiveness and safety of CTC detection in patients with breast tumor, and to conduct the following analysis. Methods: One hundred and ninety patients who received treatment in six leading Chinese cancer centers were involved from April to August in 2016. Among which, 127 patients were diagnosed as metastatic breast cancer, and the other 63 patients as benign breast tumors. Results: In metastatic breast cancer group, 74.8%(95/127) were CTC positive. While in benign tumor group, they were all CTC negative patients. The area under the Receiver Operating Characteristic curve were 0.832(95%CI: 0.784-0.879). The sensitivity of Cellcollector was 74.8%, specificity was 100% (Youden index 0.748). A total of 117 patients in MBC groups received a second detection of Cellcollector after 3-4 weeks, among which 44.4% (52/117) were CTC positive patients. The incidence of adverse events and severe adverse events in MBC was 66.9%(85/127) and 39.8% (53/127). Furthermore, we used Cellcollector to perform the HER2 testing and gene sequencing. Conclusions:In vivo isolation of CTCs overcomes blood volume limitations compared to other approaches. The further application of molecular typing and gene typing might help to implement CTC-based "liquid biopsies" into clinical decision making.